Nonsyndromic cleft lip with or without cleft palate (CL/P;
MIM 119530), a common birth defect, is a genetically complex
trait. Several genetic and environmental factors seem to be
involved in the development of this malformation [Carinci
et al., 2003]. Nevertheless, CL/P also occurs as a part of many
single gene syndromes, and some of these genes may also have
roles in nonsyndromic CL/P.
Suzuki et al. [2000] showed that the rare autosomal recessive
syndrome CL/P-ectodermal dysplasia (CLPED1; MIM 225060)
is caused by the loss-of-function of PVRL1 gene, which encodes
nectin-1, a cell-to-cell adhesion molecule. The same group
demonstrated that heterozygosity of the nonsense mutation
W185X is a genetic risk factor for nonsyndromic CL/P in
northern Venezuela [Sozen et al., 2001].
To verify whether the W185X mutation is a genetic risk
factor for nonsyndromic CL/P in the Italian population,
71 familial CL/P belonging to 71 different pedigrees, 75
sporadic CL/P, and 100 unrelated unaffected individuals were
enrolled in this study. The W185X mutation is a singlenucleotide
change G!A that creates a StyI restriction
endonuclease site. Therefore, a 160 bp segment of the exon 3
containing the mutation was amplified by PCR using the
following primers: W185X.for 50CCACCAATTGGATAGAGGGTA30
and W185X.rev 50CGGATCTCCTGGTACTCTGC30.
Amplimers were digested with StyI restriction endonuclease,
electrophoresed on 2.5% agarose gel, and visualized by
ethidium bromide. Positive controls, containing the mutation
generated by site-directed mutagenesis (www.buckinstitute.
org/benz/prot/prot12.htm), were included to verify the assay
efficiency in each test.
Of the 146 CL/P patients and of the 100 unaffected
individuals analyzed in this study for the presence of the
W185X mutation in the PVRL1 exon 3, none was positive.
The results of this investigation indicate that in Italy the
W185X mutation is not common and in turn, it does not
constitute a risk factor for nonsyndromic CL/P. As suggested by
Suzuki et al. [2000], since the PVRL1 gene product constitutes
a receptor for herpesviruses, in the Margarita Island population
the mutation may be selected positively for an increased
resistance to infections of the carriers.
Our findings significantly differ from those previously
observed in the Venezuelan population [Sozen et al., 2001].
This discrepancy likely reflects the complex etiology of the
CL/P malformation. Indeed, the numerous genetic and environmental
factors involved probably contribute differently to
the development of the malformation in distinct populations.

Nonsyndromic cleft lip with or without cleft palate (CL/P;
MIM 119530), a common birth defect, is a genetically complex
trait. Several genetic and environmental factors seem to be
involved in the development of this malformation [Carinci
et al., 2003]. Nevertheless, CL/P also occurs as a part of many
single gene syndromes, and some of these genes may also have
roles in nonsyndromic CL/P.
Suzuki et al. [2000] showed that the rare autosomal recessive
syndrome CL/P-ectodermal dysplasia (CLPED1; MIM 225060)
is caused by the loss-of-function of PVRL1 gene, which encodes
nectin-1, a cell-to-cell adhesion molecule. The same group
demonstrated that heterozygosity of the nonsense mutation
W185X is a genetic risk factor for nonsyndromic CL/P in
northern Venezuela [Sozen et al., 2001].
To verify whether the W185X mutation is a genetic risk
factor for nonsyndromic CL/P in the Italian population,
71 familial CL/P belonging to 71 different pedigrees, 75
sporadic CL/P, and 100 unrelated unaffected individuals were
enrolled in this study. The W185X mutation is a singlenucleotide
change G!A that creates a StyI restriction
endonuclease site. Therefore, a 160 bp segment of the exon 3
containing the mutation was amplified by PCR using the
following primers: W185X.for 50CCACCAATTGGATAGAGGGTA30
and W185X.rev 50CGGATCTCCTGGTACTCTGC30.
Amplimers were digested with StyI restriction endonuclease,
electrophoresed on 2.5% agarose gel, and visualized by
ethidium bromide. Positive controls, containing the mutation
generated by site-directed mutagenesis (www.buckinstitute.
org/benz/prot/prot12.htm), were included to verify the assay
efficiency in each test.
Of the 146 CL/P patients and of the 100 unaffected
individuals analyzed in this study for the presence of the
W185X mutation in the PVRL1 exon 3, none was positive.
The results of this investigation indicate that in Italy the
W185X mutation is not common and in turn, it does not
constitute a risk factor for nonsyndromic CL/P. As suggested by
Suzuki et al. [2000], since the PVRL1 gene product constitutes
a receptor for herpesviruses, in the Margarita Island population
the mutation may be selected positively for an increased
resistance to infections of the carriers.
Our findings significantly differ from those previously
observed in the Venezuelan population [Sozen et al., 2001].
This discrepancy likely reflects the complex etiology of the
CL/P malformation. Indeed, the numerous genetic and environmental
factors involved probably contribute differently to
the development of the malformation in distinct populations.